viii

CONTENTS.

CHAPTER IV.

PAGE

The sense of hearing-Organs of sound-Mollusca — Crustacea-

Insects Locusts — Grasshoppers — Crickets — Cicadas

Beetles—The bombardier beetle-Paussus-Death-watch-

Burying beetles-Weevils—Cockchafers — Variety of organs

of sound among beetles–Diptera-Hymenoptera-Ants-

Bees--Sounds produced in flight-Power of varying sound

-Butterflies—Moths-Centipedes-Spiders-Power of hear.

ing in insects–Sense of hearing in insects

60

CHAPTER V.

The organs of hearing-Structure of the human ear— The organ

of Corti-Mode of action of auditory organs-Organs of

hearing in the lower animals—Medusæ--Auditory hairs-

Mollusca-Annelides—Crustacea-Use of grains of sand as

otolithes-Ear in tail of Mysis–Mode of hearing-Organs

of hearing in insects—Seat of the sense of hearing in insects

-Different seats of organs of sense-Ears in legs of crickets

-Ear of grasshoppers-Structure of ear -Auditory rods-

Ear of locusts-Peculiar structure in leg of ant--Origin of

ear-Ear of fly-Peculiar sense-organs - Auditory rods in

beetles-Position of auditory rods—Chordotonal organs-

Auditory hairs of antennæ of gnat-Sympathetic vibrations

- Organs of hearing in various parts of body

77

CHAPTER VI.

The sense of sight—Three possible modes of sight-Different

forms of eye-The vertebrate eye-Structure of the eye-

The retina–The rods and cones—The blind spot in the eye

-Inversion of the rods—The pineal gland--The rudimentary

median eye—The median vertebrate eye—The organs of

vision in the lower animals-Color-spots—Echinoderms-

Worms—Molluscs—Cuttle-fish-Compound eyes in Molluscs

-Arca-Spondylus-Pecten—Onchidium-Sense-organs of

Chiton

118

...

CHAPTER VII.

The organs of vision in Insects and Crustacea-Ocelli—Compound

eyes - Cornea - Crystalline cones Retinula — Pigment-
Different forms of eyes-Structure of the optic lobes-Eyes

of Crustacea-Structure of eye-Mysis—Corycæus-Copilia

-Calanella-Limulus-Scorpions-Light-organs of Eu-

phausia-Mode of vision by compound eyes — Müller's theory

of Mosaic vision-Images thrown by the cornea-Objections

to other theories - Position of the image-Absence of power

of accommodation-Absence of retina - Summary-On the

power of vision in insects — Experiments on vision of insects

-On the function of ocelli – Difficulty of subject-Experi-

ments -Short sight of ocelli—Ocelli of cave-dwelling spiders

-Probable function of ocelli

146

CHAPTER VIII.

On problematical organs of sense-Muciferous canals of fish-

Deep-sea fish-Light-organs-Living lamps—Problematical

organs in lower animals—Medusæ-Insects-Crustacea-

Difficulty of problem-Size of ultimate atoms—The range

of vision and of hearing_Unknown senses—The unknown

world

182

...

...

CHAPTER IX.

On bees and colors --Experiments with colored papers—Dr.

Müller's objections-Reply to objections—Preferences of

bees—The colors of flowers

... 194

CHAPTER X.

On the limits of vision of animals-Ants and colors—The

ultra-violet rays—The limits of vision in ants-Supposed

perception of light by the general surface of the skin-

Experiments with hoodwinked ants—Confirmation of my

experiments on ants-Experiments with Daphnias—Daph-

nias and colors-Preference for yellowish green-Experi-

ments-Limits of vision of Daphnias-Perception of

ultra-violet rays-Objections of M. Merejkowski-Suggestion

that Daphnias perceive brightness, but not color-Further

experiments—Evidence that Daphnias perceive differences

of color

202

...

CHAPTER XI.

On recognition among ants—Experiments with intoxicated ants

-Evidence against recognition by means of a sign or pass-
word-Experiments with ants removed from the nest as

X

CONTENTS.

PAGE

pupa and subsequently restored-Experiments with drowned

ants-Recognition after a year and nine months-Supposed

recognition by scent-Recognition by means of the antennæ 232

CHAPTER XII.

On the instincts of solitary wasps and bees-Instinct of render-

ing victims insensible--Origin of instincts-Habits not

invariable-Change of instincts-Bembex-Odynerus-Am-

mophila-Modifiability of instincts-Differences under

different circumstances-Origin of the habits of Sphex-

Race differences-Limitation of instinct-Toleration of para-

sites—Cases of apparent stupidity-M. Fabre's experiments

-Limitation of instinct-Instinct and habits - Inflexibility

of instinct - Different habits of males and females-Arrange-

ment of male and female cells—Power of mother to regulate

the sex of the young

242

CHAPTER XIII.

On the supposed sense of direction-Experiments with bees-

Whirling bees-Behaviour of bees if taken from home-

Mode of finding their way-Experiments with ants-Mr.

Romanes' experiments—No evidence of separate sense

of direction ...

262

...

CHAPTER XIV.

On the intelligence of the dog-Education of the deaf and dumb

-Laura Bridgman-Application of the method followed

with the deaf and dumb to animals – My dog Van and his

cards–Use of cards with words on them, “ food," " water,"

“ tea,” etc.—Recognition of the separate cards—Association

of the card with the object-Realization that bringing a

card was a request-Attempts to convey ideas-Arithmetical

powers of animals—Previous observations—Supposed powers

of counting-Mr. Huggins's experiments-Conclusion

272

LIST OF ILLUSTRATIONS.

FIGURE

PAGE

3

3

5 5

6

8

1. Diagram to illustrate possible origin of a sense-organ. c, Cuticle;

h, cellular or hypodermic layer 2. Diagram to illustrate possible origin of a sense-organ. C, Cuticle;

h, cellular or hypodermic layer 3. Diagram to illustrate possible origin of a sense-organ. c, Cuticle;

h, hypoderm ; n, nerve 4. Diagram of further stage in the origin of a sense-organ 5. Diagram illustrating a second possible origin of a sense-organ 6. Diagram of further stage in the origin of a sense-organ 7. Section through the simple eye of a young Dytiscus larva. h,

Hypoderm; l, lens; o, optic nerve; 9, P, modified hypodermic

cells; r, retina 8. Auditory vesicle of Ontochis 9. Pacinian corpuscle. a, Neurilemma; b, nerve-fibril; c, capsule;

d, peculiar fibres ; e, central cylinder 10. Papilla from the surface of the hand, X 350. a, Cone-like body;

b, nerve; C, end of nerve 11. Portion of the skin of the back of the hand. The centre figure

represents the arrangement of the hairs; CP, the cold-points;

WP, the warmth-points
12. Half a cross section through the brain and hinder pair of eyes of

Nereis cultrifera. 1, Hypoderm; 2, cuticle ; 3, retina; 4,
outer corneal cells; 5, inner corneal cells ; 6, brain; 8, 8a,
two places to which the brain sends large nerves, but where

the cuticle is unaltered ; g, gelatinous body
13. Part of upper nerve-ring and tactile epithelium of Lizzia. a,

Tactile epithelium ; g, ganglionic cell; nr?, upper nerve-ring 14. Diagram of part of the skin of a sea-anemone (Actinia). dz,

Glandular cell; nz, nervous cell 15. Anterior part of body of Bohemilla comata. 1b, Tactile hair;

8

10

12

12

13

xii

LIST OF ILLUSTRATIONS.

FIGURE

PAGE

hy, hypoderm ; C, cuticle; b, anterior part of brain ; a, eye;
ne, nerve-fibrils ; o, anterior blood-vessel

13 16. Diagrammatic section through a papilla of touch of Onchidium.

a', a", two layers of the cuticle; a, biconvex thickened portion
of the cuticle ; b, enlarged epithelial cells ; b', ordinary epithe-
lial cells; C, cellular body; d, cells; n, nerve

14 17. Diagram of the structure of the soft and some of the hard parts

in the tegmentum of a shell of a Chiton (Acanthopleura spiniger),
as seen in a section vertical to the surface, and with the margin
of the shell bordering on the girdle lying in the direction of
the left side of the drawing. f, Calcareous cornea ; h, iris ;
g, lens; k, pigmented capsule of eye; n, optic nerve; r, rods
of retina; n', branches of the optic nerve, perforating the cap-
sule wall, and terminating in b', 6', b', ocular sense-organs ;
P, p, nerves to sense-organ; m, body of sense-organ cut across;
a, p, fusiform body of sense-organ entire; a, obconical termi-
nation of sense-organ ; e, nerve given off by one sense-organ
to another, 5"

15 18. Diagram of forms of hairs in insects. a, Ordinary surface hair;

b, plumose natatory hair; c, hair of touch; d, auditory hair;
e, olfactory hair; f, taste hair; n, nerve hair

16 19. Part of the proboscis of a fly (Musca)n, nerve; g, ganglionic swellings; s, tactile hairs or rods ; c, cuticle ..

17 20. Right half of eighth segment of the body of the larva of a guat

(Corethra plumicornis). EG, Ganglion ; N, nerve; %, auditory
ganglion; gb, auditory ligament; Ch, auditory rods; a, auditory
nerve; e, attachment of auditory organ to the skin ; b, attach-
ment of auditory ligament; hn, hn', termination of skin-nerve;
tb, plumose tactile hair; h, simple hair ; ty, ganglion of tactile
hair; Im, longitudinal muscle

18 21. Taste-buds of the rabbit, x 450 ..

20 22. a, Isolated taste-cells from the mouth of a rabbit; b, two covercells and a taste-cell in their natural position, X 600

20 23. Termination of the nerves of taste in the frog, showing the

ramifications of the nerve-fibres and their connections with the
cells of taste, x 600

21 24. Inner layer of skin the proboscis of Asterope candida, X 400.

a, Cuticle; b, terminal (nerve) organs; C, ganglionic cells;

d, longitudinal muscle; e, transverse muscle 25. Taste-organ of the bee. B, Horny ridge; R, R, sensory pits;

C, C, skin of the mouth ; L, muscular fibres; A, A, muscular fibres ; S, S', ab c d e f, section of the skin of æsophagus .. 26

22